Geographic variables in background radiation include altitude (higher altitude results in higher cosmic radiation exposure) and percentage of radioactive gas in the atmosphere. In Australia, the average background radiation is 1.5-2 mSv/year 1, while in the USA it is 3.2 mSv/year 2.

Sometimes but not always medical exposure is considered part of background radiation with average doses of 1.7 mSv (Australia) to 3.0 mSv (USA) per person per year 1,2, although this figure will vary dramatically depending on availability and technology.